Drum’s analogy for the development of artificial intelligence is filling Lake Michigan an exponential ounce at a time:

Suppose it’s 1940 and Lake Michigan has (somehow) been emptied. Your job is to fill it up using the following rule: To start off, you can add one fluid ounce of water to the lake bed. Eighteen months later, you can add two. In another 18 months, you can add four ounces. And so on. Obviously this is going to take a while.

It’s a simple calculation. After 30 years you’ve added about a gallon of water. By 2010 you’ve got “a few inches of water here and there”. By 2025 Lake Michigan is refilled.

Drum then explains his analogy:

I started in 1940 because that’s about when the first programmable computer was invented. I chose a doubling time of 18 months because of a cornerstone of computer history called Moore’s Law, which famously estimates that computing power doubles approximately every 18 months. And I chose Lake Michigan because its size, in fluid ounces, is roughly the same as the computing power of the human brain measured in calculations per second.

In other words, just as it took us until 2025 to fill up Lake Michigan, the simple exponential curve of Moore’s Law suggests it’s going to take us until 2025 to build a computer with the processing power of the human brain.

And its troubling implications for human society over the next 30 or so years:

During the Industrial Revolution, machines were limited to performing physical tasks. The Digital Revolution is different because computers can perform cognitive tasks too, and that means machines will eventually be able to run themselves. When that happens, they won’t just put individuals out of work temporarily. Entire classes of workers will be out of work permanently.

Read the whole piece here. And read Drum’s related blog posts here, here, here, here, with more likely in the coming days here.

This is one of those pieces that could be depressing. The alternative is to begin using it as a plausible framework for understanding numerous small, seemingly insignificant changes in the economy, and then start figuring out how to deal more effectively with those changes.